Grapevine botryosphaeria dieback (Lasiodiplodia viticola)

Symptoms often appear as a sudden dieback of canes or entire cordons, typically observed in mid-to-late summer during periods of high physiological demand.

Cross-sections of infected trunks or branches reveal dark brown or black necrosis, which disrupts the transport of water and nutrients to the canopy.

Small, black, pimple-like structures called pycnidia can be seen emerging through the bark of dead or dying wood, especially under humid conditions.

Affected vines often display reduced vigor, shortened internodes, and stunted leaf growth before the eventual death of the affected arm or whole plant.

• Vascular necrosis in wood
• Leaf chlorosis and wilting
• Cordon dieback
• Black pycnidia on bark
• Shriveled berries on affected shoots

The disease is caused by the fungus Lasiodiplodia viticola, a pathogen belonging to the Botryosphaeriaceae family that infects the woody tissues of grapevines.

This pathogen survives as mycelium or pycnidia within infected woody parts, serving as a reservoir for infection throughout the growing season.

The fungus enters the host through wounds, pruning cuts, or natural cracks caused by frost or mechanical damage, colonizing the xylem and phloem.

Conidia are spread through the vineyard by rainfall, wind, and contaminated pruning tools, facilitating rapid dispersal under favorable environmental conditions.

The biological complexity of Lasiodiplodia viticola makes it a persistent threat in vineyards, as it remains latent in the wood until stress triggers decline.

Warm and humid weather conditions are highly conducive to the proliferation of Lasiodiplodia viticola and the release of its spores.

Mechanical stress, including pruning, training, or damage from heavy machinery, significantly increases the susceptibility of vines to fungal infection.

Poor vineyard hygiene, such as leaving infected prunings on the ground, creates a constant source of inoculum that can infect nearby healthy plants.

High planting densities combined with poor canopy management promote humidity retention, which favors the germination and penetration of fungal conidia.

Vineyard sites with history of environmental stress, such as drought or extreme heat, show higher rates of fungal colonization due to weakened vine defense systems.

The damage caused by this pathogen is severe, leading to the irreversible decline and death of grapevines, which necessitates costly replanting.

Yield quality and quantity are drastically reduced, as infected vines struggle to maintain physiological balance, leading to poor fruit ripening.

The infection spreads systematically within the woody structure, making it difficult to detect until significant damage has already occurred.

The economic impact is profound due to the loss of productive, mature vines that are the backbone of high-quality vineyard output.

Furthermore, the pathogen can be disseminated through propagation material, posing a risk of introducing the disease into new, unaffected areas.

Strict sanitation practices, including the removal and destruction of dead wood and infected plant debris, are fundamental for disease management.

Disinfecting pruning tools with appropriate chemical solutions after every cut is crucial to prevent the transfer of fungal spores between healthy vines.

Applying protective wound sealants to pruning cuts helps create a barrier against airborne spores, reducing the risk of new infections.

Using healthy, certified disease-free propagation material is the most effective long-term strategy for maintaining vineyard longevity.

Integrated management, including balanced vine nutrition and stress mitigation, helps bolster the plant's natural ability to withstand pathogen pressure.